I. Field of the Invention
The present invention relates generally to a method and apparatus for treating cutaneous vascular lesions and, more particularly, to such a method and apparatus in which the cutaneous vascular lesions are treated by simultaneously cooling the site of the lesions while delivering laser light to the site.
II. Description of the Prior Art
A cutaneous vascular lesions, such as telangiectasia or spider capillaries of the lower extremities, is a condition where previously microscopic blood vessels have become dilated. They are visible through the skin appearing as red, blue or purple variably tortuous lines or patches. The causes of this abnormal enlargement of vessels are not fully understood, and although they are of little medical consequence their cosmetic significance can be great. This is a widespread problem that may cause much concern for those afflicted.
Sclerotherapy is the treatment that is now used. It is considered to be safe, appropriate and relatively effective. Sclerotherapy entails the intravascular injection of one of a variety of agents into the abnormal blood vessels. The substance injected injures the inside of the capillary causing it to shrink or disappear. This treatment is variably painful, approximately seventy percent (70%) effective and usually requires one to two months waiting before improvement can be seen. There can occur, unpredictably, echymotic or hyperpigmented marks as a side effect and these marks may take many months to fade. Scabbing of injection sites, perhaps due to extravasation of the injected sclerosing agent, may also occur.
Laser surgery with a variety of different lasers (CO2, Argon, tunable dye) has been utilized in an attempt to find a less painful, more effective treatment. The desire to avoid side effects has also prompted a search for alternative treatment. To date, the ability to improve the outcome by virtue of laser surgery has, unfortunately, not been possible for reasons explained below.
The disadvantages of sclerotherapy, as described above, include the pain of treatment, only partial improvement, and the possibility of long term discoloration that can be more noticeable than the telangiectasia. Although laser surgery (Argon or tunable dye) hurts less than sclerotherapy, it has not offered an improved result. Due to the interaction between laser light and melanin pigments in the epidermis that overlies the target vessels, there can be long term hyperpigmentation, persistent scabs and sometimes permanent scarring.
U.S. Pat. No. 4,122,853 to Smith, which issued on Oct. 31, 1978, provides an infrared laser photocautery device. There is provided means for delivering a liquid through a passageway for irrigating the area being treated. The fluid is not used for cooling, and the utility of the device is primarily for photo-cauterizing intraocular muscular tissue.
U.S. Pat. No. 4,381,007 to Doss, which issued on Apr. 26, 1983, relates to a multipolar probe apparatus using radio frequency energy to reshape the cornea of an eye. The surface of the cornea is flushed continuously with an electrically conductive liquid coolant during the operation. No lasers are involved, and the use of the apparatus is limited to reshaping corneas.
U.S. Pat. No. 4,559,942 to Eisenberg, which issued on Dec. 24, 1985, is a method of using a laser for cataract surgery. The laser passes through a probe to the target tissue and an air cushion is maintained between the probe and the target tissue to prevent physical contact between the radiation outlet of the probe and the target tissue during laser irradiation. At column 4, lines 39-41, it is emphasized that due to air cushion between the probe and the target tissue, the laser radiation passes to the tissue with little loss of heat, thus indicating that it is Eisenberg's intent to conserve, not to dissipate, heat.
U.S. Pat. No. 4,608,979 to Breidenthal, et al, which issued on Sep. 2, 1986, is directed to nonsurgically fragmenting of kidney stones by an apparatus which produces focused shock waves. A truncated ellipsoidal reflector is positioned against the patient with one focus coincident with the stone. The reflector is filled with a liquid medium having an acoustical impedance similar to living tissue. A laser beam is focused at the remaining focus, thereby producing a shock wave which is coupled through the liquid medium and the patients tissue and focused at the stone, to impart a fragmenting stress to the stone. The liquid medium is not used for cooling purposes.
European Patent application No. 073,617 to Pemberg, which has a priority dated of Aug. 25, 1981, provides a laser dental hard piece with a water/air supply tube. There is provided means for pulsating the water alternately with the laser beam if the laser beam will not function efficiently in a water-vapor atmosphere. There is no mention of using water or air for cooling.
In Plasti. Reconstr. Surg. 6902:78 (1982) in an article titled "Chilling Port Wine Stains Improves The Response To Argon Laser Therapy" by B. A. Gilchrest, S. Rosen and J. M. Noe, the data obtained in this study suggests the potential benefit of port wine lesional modification by chilling the lesional sites by applying ice thereto for 2 to 3 minutes and then subjecting the sites to Argon laser therapy. It is further suggested that the benefit is due to reduced heat injury of nonvascular elements in the skin.
In Plasti. Reconstr. Surg. 75.1:42-45 (1985) in an article titled "The Benefit Of Chilling In Argon-Laser Treatment Of Port-Wine Stains" by B. Dreno, T. Patrice, P. Litoux and H. Barriere, the authors compare results obtained in Argon laser treatment of port-wine stains with and without preliminary chilling, noting that the success rate is considerably greater with the former procedure (68.6 percent) then with the latter (37.5 percent). The patients were classified as having good or unsatisfactory results four months after treatment. A good result corresponded to an evident blanching of the treated area, and an unsatisfactory result corresponded to slight or no blanching of the treated area.
It should be noted that in the latter two studies, Argon laser treatment and cooling did not occur simultaneously.
The following patents were cited during the prosecution of the parent to this continuation-in-part application. U.S. Pat. No. 3,821,510 to Muncheryan, which issued on Jun. 28, 1974, is directed to a hand-held laser beam transmitting and focusing device in which there is provided means for selectively passing therethrough one or more fluids simultaneously with the operation of the device.
U.S. Pat. No. 3,307,553 to Liebener, which issued on Mar. 7, 1967, is directed to an apparatus for cooling irradiated skin areas. It provides a container having a parallel faces that are perpendicular to the treatment beam, but uses cooling medium flowing therethrough, not a stationary container, for cooling of the skin areas.
U.S. Pat. No. 3,967,627 to Brown, which issued on Jul. 6, 1976, is directed to hot/cold applicator system that provides for the use of a heat exchanger and re-circulation of recooled liquid.
U.S. Pat. No. 4,140,130 to Storm III, which issued on Feb. 20, 1979, is directed to an electrode structure for emitting electromagnetic radiation.
These patents neither provides a transparent container or medium nor the positioning of the cooling medium between the laser beam source and the target area as provided for the present application.